Applicant hereby claims priority in and incorporates by reference in its entirety Japanese Application No. 2001-194936 (P), filed Jun. 27, 2001.
The present invention relates to an ashing apparatus, an ashing method and a method for manufacturing semiconductor devices, which can reduce foreign matters that may remain on a body to be processed.
FIG. 7 shows a cross-sectional view to describe a conventional method for manufacturing a semiconductor device.
First, a TiN film 102 is formed by sputtering on an underlying film 101. A variety of films can be used for the underlying film 101; for example, a film having a stacked layered structure composed of a TiN film as an underlying layer and an Al alloy film as an upper layer may be used. Next, a BARC 103 that functions as an anti-reflection coating is formed on the TiN film 102. Then, a photoresist film is coated on the BARC 103, and the photoresist film is exposed and developed to thereby form a resist pattern 104a on the BARC 103.
Then, the BARC 103 is dry-etched using the resist pattern 104a as a mask. Next, the TiN film 102 is dry-etched using the resist pattern 104a as a mask.
Next, the underlying film 101 composed of the Al alloy film and TiN film is successively etched. Then, the wafer is removed from the etching apparatus into the atmosphere, and the wafer is introduced in the chamber of the ashing apparatus to thereby remove the resist pattern 104a and the BARC 103 by ashing.
In the conventional method for manufacturing semiconductor devices described above, an etching of the Al alloy film and an etching of the TiN film are conducted in the same etching apparatus. For this reason, products (Alxe2x80x94Cl) generated upon etching the Al alloy film by a Cl containing gas remain in the etching chamber, and there are occasions that the products 105 may remain on the wafer (on underlying film 101) when the TiN film 102 is etched, as shown in FIG. 7. The residual products 105 may react with water in the atmosphere and may grow as foreign matters. These foreign matters become the source of undesirable particles.
FIGS. 8(a)-(c) show cross-sectional views illustrating another conventional method for manufacturing semiconductor devices.
First, as shown in FIG. 8(a), a TiN film 102 is formed by sputtering on an underlying film 101. Next, a BARC 103 that functions as an anti-reflection coating is formed on the TiN film 102. Then, a photoresist film is coated on the BARC 103, and the photoresist film is exposed and developed to thereby form a resist pattern 104a on the BARC 103.
Then, as shown in FIG. 8(b), the BARC 103 is dry-etched using the resist pattern 104a as a mask. Next, the TiN film 102 is dry-etched using the resist pattern 104s as a mask.
Next, the wafer is transferred from the etching apparatus into the ashing chamber, to thereby remove the resist pattern 104a and the BARC 103 by ashing. In this instance, the temperature of the stage in the ashing chamber on which the wafer is mounted is at a high temperature of about 250xc2x0 C. In this ashing process, after the wafer is placed on the stage at a high temperature, the wafer is maintained on the stage for about 15 seconds-30 seconds to adjust and stabilize the pressure inside the chamber.
In the other conventional method for manufacturing semiconductor devices described above, the time for adjusting and stabilizing the pressure is relatively long, such that there are occasions that the BARC 103 hardens. For this reason, even if the resist pattern 104a and the BARC 103 are removed by ashing, BARC residues 106 may remain as ashing residues on the TiN film 102. As a result, the reliability of the semiconductor device is lowered.
Embodiments relate to an ashing apparatus that ashes a photoresist film on a body in which a conducting film has been etched using the photoresist film as a mask, the apparatus including an ashing chamber and a stage for mounting a body to be processed disposed in the ashing chamber. The apparatus also includes a gas introduction system that introduces an ashing gas adjacent to a body to be processed mounted on the stage, and a plasma system that forms a plasma in at least one ashing gas introduced by the gas introduction system, wherein an ashing gas includes H2O gas.
Embodiments also relate to an ashing method that ashes a photoresist film on a body to be processed in which a TiN film is etched using the photoresist film as a mask, the method including disposing a body to be processed in an ashing chamber. The method also includes a first step of introducing a first ashing adjacent to the body to be processed, and forming a plasma in the first ashing gas and ashing the photoresist film. The method also includes a second step of introducing H2O gas adjacent to the body to be processed, and forming a plasma in the gas and ashing foreign matter, if present, on the body to be processed.
Embodiments also relate to a method for manufacturing a semiconductor device, the method including a first step of forming a TiN film on an underlying film. The method also includes a second step of coating a photoresist film on the TiN film, and exposing and developing the photoresist film. The method also includes a third step of etching the TiN film using the photoresist film as a mask, by using an etching apparatus that etches an Al alloy film. The method also includes a fourth step of introducing a mixed gas containing O2 gas and N2 gas adjacent to the photoresist film, and forming a plasma in the gas and ashing the photoresist film. The method also includes a fifth step of introducing H2O gas adjacent to the TiN film, and forming a plasma in the gas and ashing foreign matter, if present, on the TiN film.
Embodiments also relate to a method for manufacturing a semiconductor device, the method including a first step of forming a TiN film on an underlying film, and a second step of forming a BARC on the TiN film. The method also includes a third step of coating a photoresist film on the BARC, and exposing and developing the photoresist film. The method also includes a fourth step of etching the BARC and the TiN film using the photoresist film as a mask, by using an etching apparatus that etches an Al alloy film. The method also includes a fifth step of introducing a mixed gas containing O2 gas and N2 gas adjacent to the photoresist film, and forming a plasma in the gas and ashing the photoresist film and the BARC. The method also includes a sixth step of introducing H2O gas adjacent to the TiN film, and forming a plasma in the gas and ashing foreign matter, if present, on the TiN film.
Embodiments also relate to an ashing method that ashes a photoresist film on a body to be processed in which a conducting layer has been etched using the photoresist film as a mask, the method including disposing a body to be processed in an ashing chamber. The method also includes introducing a first gas into the chamber, forming a plasma in the first gas and ashing the photoresist film. The method also includes introducing a second gas comprising H2O gas into the chamber, forming a plasma in the second gas and ashing foreign matter, if present, on the body to be processed. The first gas and the second gas have different compositions.